Piston for internal-combustion engines



Oct. 22,1946. HARRAH 2,409,852

PISTON FOR INTERNAL-COMBUSTION ENGINES Filed March 19, 1945 Y fmmun Ven'ibr:

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Patented Oct. 22, 1946 PISTON FOR INTERNAL-COMBUSTION ENGINES John L.Harrah, Akron, Ohio Application March 19, 1945, Serial No. 583,545

4 Claims.

This invention relates to pistons, but more particularly to a sectionalpiston construction, especially adapted for use in internal combustionengines, automobile, truck, bus, tractor, and in fact other types ofengines.

The piston rings now used in internal combustion engines are positionedin new ring grooves at an exact fit. with a, close precision clearance.After a limited number of miles of engine wear, the piston rings wearthe top and bottom surfaces of the ring grooves.

When the rings are loose in the grooves they will allow the motor oilfrom the crank-case, to pass under the rings, to the back of the rings,and out across the top. Because of the heat, part of this oil willcarbonize and the balance will pass to the combustion chamber. Thecarbon lodging around and in the back of the rings will cause the lossof their resiliency and they become a sludged dead Weight. Part of theoil which has proceeded to the combustion chamber will also carbonizeand it will not let the valves seat properly. The rest of the oil in thecombustion chamber will foul the spark plugs and then pass unused outthrough the exhaust.

After the piston rings have lost their resiliency and have becomeweighted with sludge and carbon, they cannot retain the oil in thecrank-case, holding the compressed gases above the pistons, nor controlthe blow-by.

When the engines are equipped with removable head pistons, at any time,the accumulated carbon can be removed, the Valves ground, and new ringsinstalled, in one operation, from the top of the motor. With new ringsproperly working in new grooves, they will hold the compressed gasesabove the pistons, control the blow-by, and retain the motor oil in thecrank-case, which will insure proper lubrication of the other movingparts of the motor at all times.

The object of this invention is, therefore, the efiecting of meanswhereby the piston rings may be removed and renewed from the top of themotor, without thus removing the entire piston, nor disturbing the otherassembled parts and mountings of the engine.

Another object of the invention is to provide a sectional piston wherebythe top portion, in which the rings are carried, can be obtainedseparately from the skirt portion, with new piston rings properlyassembled.

The invention is fully disclosed in the following specification, ofwhich the accompanying drawing forms a part, in which the separate partsof the piston improvement are designated by suitable referencecharacters in each of the views, and in which:

Figure 1 is a top plan view of the removable piston head assembled.

Figure 2 is a sectional view on the line 22 of Figure 1, showing thewrist pin and connecting rod in position. i

Figure 3 is a bottom plan view or the top portion.

Figure 4 is a side view of the piston showing immediately above it theremovable head. portion in section.

Figure 5 is a top plan view of the skirt section.

Figure 6 is a side view of the piston assembled with a detail sectionalview of the ring section showing the lock-thread set screw and thefillers inposition.

In this illustrative construction I have shown for the purpose ofcarrying my invention into effect, Figure 2 a well known trunk typepiston having the connecting rod 1 connected thereto by the wrist pinbearings 3. Th main body of this piston, is of course, of cylindricalconstruction, open at both axial ends, the lower portion of said bodyforming a skirt, and the upper portion the ring section.

The skirt section 6, open at both axial ends, a wall at the upper endthereof, said .wall having an inward, upward projecting hollow neck 5;said hollow neck having complemental L shaped apertures |2--l2, withthelong sides of the L open and extending upward centrally spaceddirectly above the wrist pin boss centers; said piston skirt wall havingan annular recessed shoulder A somewhat smaller in diameter than theinterior of the ring section, while the exterior of both portions arealike.

The ring section 1, a hollow cylindrical portion, having an upper wall,said ring section being open at the lower end, with a correspondingannular recessed shoulder 8. In the periphery of the ring section, aplurality of annular spaced ribs forming intermediate thereof pistonring reshaped apertures iZ-IZ in the skirt section,

down about the hollow neck of the piston; by rotating the ring section apartial turn the ribs I!!IB are positioned snugly into the parallelcavities of th L shaped apertures in the skirt section.

To additionally secure the ring section in this position, through theholes HH in the face of the piston top, lower the fillers I3 into thelong ides Qf t e L shaped a ertu s n th kirt se tion, then screw thelock-thread set screws M downward into suitable tapped bores in saidpiston top, thus no vibration nor direct pull can sepa a l e wq s sti es3 2s i l stra ve on act en'sbqw may b modified in various respectswithout departing ir n? t e iri of m n en n nd t, wi l be understoodthat it ismy intention to include all suc medilfiea iae i t cene o theane c a m i i What I claim as new and desire to secure by Letters ate ta Pist a h l qw ylindr a od Open bat axia en s he we Deiti s f S bo twinn a Skirt, Wrist pi bea ings n aid bp v positioned immediately abovesaid skirt; the upe Par es aid bod i smaller d am te to term u rd esenteteppe Shoulder, W' a u ward i iec m e s r e s a d a s s-an lly a rang rd ced Parties sa d h l e 91; hav m m d k ap d ape r s a a c ndrica i91erti e stormed w h n m a iin r ere sa d in s c on. hav n m an a, si e wal e s osine dow wa dly pr ent cavityfthe lower edge of said wall beingstepped fit. sai ho ld r; a d r n section rqvi w th wa m te ribs wh h oe n ar f m the dewal t r f interac n lo nefctio ns with said L shapedapertureson said reducedportion by a rotary movement of said s'e'c'tiom'inserts positioned through suitable bores said top'wall snugly receivedin said L apertures in skirt section; said inserts securely held inposition with application of lock-thread set-screws firmly screwed intosuitable tapped bores in piston top.

2. In a piston, a hollow cylindrical skirt portion, a wall at the upperend thereof, open at both axial ends, an inwardly recessed hollow neckprojecting upward from said wall, having compleniental L shapedapertures; a hollow cylindrical ring section, having an upper wall, saidring section being open at the lower end, said ring section providedwith a plurality of spaced, parallel, circumferentially extending ribsforming grooves therebetween for receiving piston rings; said ringsection provided with complemental ribs which project inwardly from theside Wall thereof for inter-locking connections with said L shapedapertures in said skirt section by rotating said ring section a partialturn; through suitable bores in top wall of said ring section, meansthus to prevent rotation of ring section while the piston is in motion.v

3. In a piston, a skirt portion, open at both axial ends, having ahollow neck at its upper end thereof; a removable ring section, wherebythe piston rings may be carried; complemental ribs diametrically locatedin'the interior of said ring section said skirt portion havingcornplemental L shaped apertures for snugly receiving said. complementalribs on said ring section, engageable by a partial rotation of -saidring section; inserts lowered through face of said piston top, receivedin said skirt apertures, to firmly engage said detachable sectionsl l 4.In a piston, a skirt portion, open at both axial ends, having a hollowneck at itsupper end thereof; a removable ring section for oil andcompression rings, whereby the piston rings'n ay be carried;complemental ribs diametrically located in the interior of said ringsection, said skirtportionhaving complemental' L shaped apertures forsnugly receiving said complemental ribsof said ring section; en'gageableby a partial rotation of said ring. section; means operable from theupper face of said ring section for detachably securing the ring sectionupon said skirt section; said ring section provided with a'circumferentially. extending series of bores which extend through thewall thereof from the inner wall of the oil rin and they compressionring grooves.

JOHN .4- AR H;

